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#1 2017-08-27 16:56:54

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
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Mars Insitu Fuels made from atmosphere, regolith, water

We have known for some time that when we go to mars that we will need to be able to lesson the connection back to earth for lots of things and fuels for return flights are just one of those items.

Carbon Hydrogen with Oxygen seem to be the main ingredients for these.

CH = Carbyne
CH2 = CarBene
C6H5CH3 or C7H8 = Toluene
CH4 = Methane

ect...

What are the others; that we can make once we have the means to make them on mars....

Corrected Toluene

Last edited by SpaceNut (2017-08-28 16:32:23)

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#2 2017-08-27 17:29:03

RobS
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From: South Bend, IN
Registered: 2002-01-15
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

Space Nut, you seem to be asking "what are all the organic compounds we can make on Mars?" The answer is millions. Of the 4 compounds you have listed, only CH4 is stable by itself. The others are fragments of molecules. Other stable compounds are C2H6, C3H8, C4H10, C5H12, C6H14, C7H16, C8H18, etc. You can also get C6H6 (benzene), which is a ring. Then there are the alcohols: CH3OH, C2H5OH, C3H7OH, etc. These are methanol, ethanol, and propanol. The sky's the limit.

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#3 2017-08-28 00:38:33

Oldfart1939
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Registered: 2016-11-26
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

Toluene is C7H8, and is a cyclic aromatic compound, not C3. C3H8 is propane.

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#4 2017-08-28 16:31:35

SpaceNut
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

Did another look and I got  C6H5CH3 or C7H8 but in response to RobS I was looking to open up other possibilities as well and not just the ones to which I meantioned as the starting point as man will need lots of others over time to be made.

Such as hydrogel's.

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#5 2017-08-28 16:55:12

RobertDyck
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From: Winnipeg, Canada
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

I originally posted this to the first Mars Society forum in 1999, before New Mars. I created a local chapter website in 2001, and created a page. I added a little to it, specifically Melamine. But it's mostly what I posted in 1999. Chemical reactions to create them are either briefly shown, or in linked web pages.
Plastics

Some chemicals:

  • hydrogen - H2

  • carbon monoxide - CO

  • methane - CH4

  • ethylene - C2H4

  • benzene - C6H6

  • toluene - C7H8

  • naphthalene - C10H8

  • phenol - C6H5OH

  • ethylene glycol, aka glycol - (CH2OH)2

  • acetone - (CH3)2CO

  • cumene - C9H12

  • terebinth, aka oil of turpentine or spirits of turpentine - C10H16

Plastics:

  • polyethylene (PE, LDPE, HDPE)

  • polypropylene (PP)

  • acrylic

  • Lexan, aka polycarbonate (PC)

  • polyvinyl chloride (PVC)

  • polystyrene (PS)

  • Mylar, aka polyethylene terephthalate (PET)

  • polybutadiene rubber (BR)

  • acrylonitrile butadiene styrene (ABS)

  • phenolformaldehyde, aka phenolic

  • Nylon

  • melamine resin

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#6 2017-08-28 17:22:22

RobertDyck
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From: Winnipeg, Canada
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

If you want fuel, the obvious one to me is trisilane: Si3H8. It's liquid between -117°C and +53°C, so liquid at any temperature on the surface of Mars. It burns in a CO2 atmosphere. Autoignition temperature is 50°C, which means in an oxygen atmosphere it will spontaneously ignite. Anything with an autoignition temperature below 55°C is called pyrophoric. The slightest spark will ignite it, so it's dangerous in an oxygen atmosphere. Some people here may be familiar with silane, aka monosilane. It's autoignition temperature is -18°C, so it spontaneously ignites upon contact with air at any temperature at KSC. It was used to ignite Shuttle's main engines. Trisilane is a bit safer to handle.

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#7 2017-08-28 17:41:17

SpaceNut
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

What I noticed was the table at the bottom of the trisilane line with Binary compounds of hydrogen which would be important as building chemistry blocks along the way to making what we need on mars sooner rather than later.

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#8 2017-10-04 04:45:38

elderflower
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

The easiest propellant to get on Mars is LCO/LOX. There is no need to dig up ice, purify it and electrolyse it. Unlike LH2 these are only moderately cryogenic so fairly easy to store on Mars. Trouble is they don't give a very high Isp but they would be probably be OK for a hopper or to operate a gas turbine for power generation or traction.
Musk proposes to make Methane. It is perfectly feasible to do so, just more complicated. However Mars methane will contain some 20% deuterons in place of Hydrogen protons giving a molecular weight of about 21 instead of the MW of 20 of earth methane. This is a 5% increase in mass of fuel in any rocket using it. Also the MW of the exhaust products will be slightly increased, so reducing the achievable Isp. Musk will have to increase his margins a little to cover for these factors.

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#9 2018-08-31 18:35:28

SpaceNut
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

http://marsforthemany.com/news/technolo … et-engine/

Note: other hydrocarbon-based fuels can also be manufactured on Mars, but they all have lower ISPs than methane, so a methane rocket engine is typically the engine most discussed. Here's a quick chart if you are interested.

Fuel_Comparisons.png

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#10 2018-12-09 19:03:17

SpaceNut
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#11 2019-03-08 18:28:07

SpaceNut
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

kbd512 wrote:

Elderflower,

Seems like a good combo to me if we're using pump-fed engines.  All we need is Martian atmosphere and electrical power.  At 3,000psi, LOX/LCO specific impulse is basically equivalent to LOX/LCH4 sea-level performance.

Carbon Monoxide and Oxygen Combustion Experiments: A Demonstration of Mars In Situ Propellants

This study seems to indicate that we'd require 27% less electrical power, too.  At some point, the total mass and complexity of all systems required to make this a reality should be considered.  LOX/LCO is low-risk compared to the non-existent LCH4 plant and ice mining equipment we'd need to make a LCH4-fueled rocket / lander work.  The Isp increase is nice, but not if it means that we just negate all of that with increased infrastructure mass required to provide the infrastructure to produce propellant.  LOX and LCO can be made using existing technology, so R&D costs would also be lower.  In the future, we could always switch to LOX/LCH4 after we find the ice, determine how to mine it, and how to build a LCH4 plant that works on Mars.

A Comparison of Preliminary Design Concepts for Liquid, Solid and Hybrid Propelled Mars Ascent Vehicles Using In-Situ Propellants

I think the Rutherford engine tech from Electron Labs that sucks the tanks dry and using battery-powered electrical turbo pumps is worth a look.  There are no propellant residuals to prevent the turbo pumps from exploding, unlike gas generators or staged combustion, and electrical control over the pumps for deep throttling.  Just like staged combustion, all the propellant goes through the combustion chamber after it's been used to regeneratively cool the combustion chamber.  The engines are so small and light that they're human-portable on Earth.

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#12 2019-03-08 18:45:20

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 15,800

Re: Mars Insitu Fuels made from atmosphere, regolith, water

I noticed its using a regular engine and simple hydrogen oxygen for ignition starting which also mean hydrogel fuels would work as well.
It also seems to be throtte able as well. As you noted requiring less power makes it ideal for a starting point as we have free life support from it from the same equipment for oxygen for crew.

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#13 2019-03-08 20:12:28

kbd512
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Registered: 2015-01-02
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Re: Mars Insitu Fuels made from atmosphere, regolith, water

SpaceNut,

We'd use something like the specialized spark plugs that the RS-25 uses to assure ignition.  You also need batteries to provide cryocooler and vacuum pump power to split the CO2 into CO and O2.  I was thinking EUV lasers.  At the right power level and pulse width, they produce CO or O2 from CO2 in a single pulse.  It's a single-pass system.  A molecular sieve would filter gas and a Dyson-style system would provide "the proper amount of suction" and spin the dust out of the vacuum pump intake.

We'd land, deploy a solar array to start making propellant, and use the giant battery to keep the propellant cold at night.  We're going to do this several times per mission in order to visit enough sites to find a suitable base location.  The good thing is that all we need is clean CO2.  If we find any water in the regolith, we only extract enough for drinking and hygiene.

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#14 2019-05-04 18:33:00

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 15,800

Re: Mars Insitu Fuels made from atmosphere, regolith, water

We are going to need to under stand mars as Martian Dust Could Help Explain Water Loss, Plus Other Learnings From Global Storm
That lack of ground moisture and the light mass dust was a key to the solar powered rovers not surviving a global reaching storm.

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